abc's jonathan karl reports from the white house. >> reporter: top congressional leaders who have been briefed on the investigation say that it bears all the hallmarks of a terrorist attack. senator dianne feinstein, the chairwoman of the senate intelligence committee, told abc news' jeff zeleny, "it could be foreign, it could be home grown, but it is terrorism." the president in his remarks to the country did not to that word. >> we still do not know who did this or why. and people shouldn't jump to conclusions before we have all the facts. but, make no mistake we will get to the bottom of this. and we will find out who did this. we'll find out why they did this. any responsible individuals, groups, will feel the full weight of justice. >> i asked senior administration officials about that. what i was told was, quote, any event with multiple explosive devices as this appears to be is clearly an act of terror and should be approached as an act of terror. but the administration makes it clear this is still an ongoing investigation. very little is known. there is no information about whe